Lithopone is rather nontoxic, due to the insolubility of its components. It has been used in medicine as a radiocontrast agent. Lithopone is allowed to be in contact with foodstuffs in the US and Europe.^[1]

Australia and New Zealand review of TiO2

The realization of neuromorphic resistive memory in TiO₂ thin films (Strukov et al., 2008) marked an important milestone in the search for bio-inspired technologies (Chua and Kang, 1976). Many research proposals urged a focus on memristivity as the common feature of two electrical models: (i) electromigration of point defects in titanium oxide systems (Baiatu et al., 1990; Jameson et al., 2007) and (ii) voltage-gated ionic channels in the membranes of biological neurons (Hodgkin and Huxley, 1952). In this regard, memristors functionally mimic the synaptic plasticity of biological neurons, and thus can be implemented in artificial and hybrid neural networks. This includes a new paradigm of future computing systems (Zidan, 2018) and biocompatible electronics such as biointerfaces and biohybrid systems (Chiolerio et al., 2017).

In a statement sent to USA TODAY on Sunday, Justin Comes, vice president of research and development for Skittles maker Mars Wrigley North America, said the company couldn't comment on pending litigation – but that its use of titanium dioxide and all Mars Wrigley ingredients are safe and manufactured in compliance with strict quality and safety requirements established by food safety regulators, including the FDA.